Drain tubes or draining holes for use in conjunction with window assemblies have been well known for years. Many of these devices are usually just an elongated channel or hole previously drilled through a window assembly prior to its installation. For example, U.S. Pat. No. 364,434 to Pitman, U.S. Pat. No. 1,882,088 to O'Connor, U.S. Pat. No. 168,869 to Bradshaw and U.S. Pat. No. 2,705,819 to Gellert et al all show window assembly structures including a hole or channel drilled directly through a solid portion of the window structure to drain accumulated moisture therefrom. While the drainage means of these above-mentioned patents are beneficial for removing moisture build-up within window assemblies, the draining holes must be drilled into the window assembly prior to installation of the window structure. Also, drilling a hole or channel is effective only when the frame is solid, which does not apply to most modern window frames which are usually extruded plastic or aluminum.
U.S. Pat. No. 1,320,864 to James and U.S. Pat. No. 2,570,336 to Fouts both show drain tubes for use in conjunction with window structures which include an elongated conduit mounted within a portion of the window assembly. However, most of these types of conduits are of complex shape, i.e. not straight, making them extremely difficult to install in existing window assemblies. Moreover, curved tubes are more expensive and more difficult to install even in factories, but have nevertheless been used because of the required configuration or geometry of the window sills which make the use of a straight tube most difficult.
It is standard practice in window constructions to make the inside sill leg height greater than the outside sill height, and this is the first line of defense for preventing rain water or water of condensation from going over the inside sill leg of the window. It is this configuration or geometry which has complicated the use of drain tubes as mentioned above, and has usually required that drain tubes be curved. Although it does not relate to a window frame, the problem is illustrated in the Tibbetts U.S. Pat. No. 3,851,420 which relates to the provision of a drainage tube in an extruded threshold for a door, attention being particularly invited to FIG. 10. Because of the geometry involved, the drain tube illustrated in curved. Similarly, in a conventional extruded window frame, the geometry of the frame has usually dictated a curved tube with all its attendant problems.
An exception is illustrated in the Giger U.S. Pat. No. 3,466,819 which shows a drainage tube containing a ball check valve. However, this is a special construction which is atypical and which, moreover, uses an extruded frame provided with a groove through its upper surface for providing access to the drain tube. Such an extruded frame is undesirable for a number of reasons including poor customer acceptance, undesirable appearance, and the provision of a large opening which is likely to accumulate not only dirt and debris, but also provide a home for undesirable insects or the like.
The patent to Hauck U.S. Pat. No. 2,891,290 discloses a window drain without a tube, but which includes a baffle or closure at the outlet end. The closure or baffle will close when the wind is blowing against it from a direction substantially perpendicular to the plane of the closure. Normally, however, such a flap valve will hang in a slightly opened position. Moreover, if the wind is blowing generally parallel to the plane of the baffle, the wind will have a tendency to pull the baffle open. A flap valve is also shown in the Hester U.S. Pat. No. 1,291,511, but here it is provided as an internal structure which greatly increases the cost and complexity of its installation.
In spite of the various attempts in the prior art, the installation of drain tubes in modern extruded windows has remained a problem for many years. Because of the geometries involved, it has normally been necessary to use a curved tube and to install it at the factory from the inside out. This has not provided a satisfactory solution, and there has been a need to have a simpler drain tube construction, and one which could be installed in the field or the factory. No straight, i.e. linear, drain tube for use in conjunction especially with extruded window frames has previously been available which is capable of being easily installed in the field within existing window assemblies. Furthermore, there is a need for a straight drain tube which is provided with a reliable closure, and well as a drain tube which can be manufactured as a single unitary structure.